Oathfeed

Chemical Composition and Formation Process

Prehnite is a calcium aluminum inosilicate mineral with the formula Ca₂Al₂Si₃O₁₀(OH)₂. It primarily consists of calcium and aluminum, with additional elements like iron and potassium. It often forms in cavities within volcanic rocks and is associated with minerals such as zeolites, calcite, and quartz. Notably, prehnite can exhibit a phenomenon known as “chatoyancy” or “cat’s eye effect”. When rotated under a light source, a bright line appears to move across the stone.

Name

The name “Prehnite” honors Colonel Hendrik Von Prehn, who discovered it in South Africa in the 18th century. Prehnite has been referred to as “Cape Emerald” due to its green color and its resemblance to emerald. This name highlights its visual appeal and the lush green hues it exhibits.

Mining, Production and Use

Prehnite appears in stalactitic, botryoidal, reniform, or globular aggregates, with small crystals showing curved faces in various locations worldwide, including South Africa, Australia, and the United States. It is mined and then cut and polished into beads, cabochons, and ornamental pieces, used in jewelry as a gemstone, and for its metaphysical properties.